The charging process of TSL series chargers consists of three steps: constant current step, constant voltage step and pulsed charging step. The charging process is specially designed for Li-ion battery packs, in order for individual cells to achieve near fully charged state without being over-charged. TSL series chargers provide protection against overload, over-voltage, over-heat, short circuit and wrong polarity connection, which exhibits high stability, high resistance to interference and ability to maximize battery lifetime.